Device for changing bending tools

ABSTRACT

A grasping device for changing bending tools on tube bending machines which includes a frame mounted over the bending machine. The grasping device includes a rotary head having independent movements in rotation, vertical motion and horizontal motion. A tool magazine is also movably carried by the portal frame independently of the rotary head.

BACKGROUND OF THE INVENTION

The present invention relates to a grasping device for changing thebending tools on a tube bending machine of standard type.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Patent EP-0 120 336 discloses a tube bending machine which is secured onits bending jig, to a support device which merely allows the clampingjaws to be changed by a combination of vertical and horizontal movementsover said bending jig.

The machine described in patent EP-0 120 336 has cycle times forperforming tool changes which are too long and which slow down theproduction of elbows or bends in the tubes. What is more, the supportdevice does not allow the simultaneous changing of the clamping jaws ormating jaws which correspond, respectively, to the moving jaw and to thefixed jaw of a standard tube bending machine.

To solve this problem, the applicant filed a patent application FR98/01,315, which describes a tube bending machine comprising abarrel-type device the purpose of which was to bring the sets ofclamping jaws comprising cavities of different shapes level with thebending head of the machine so that the one that corresponded to theexterior profile of the tube that was to be bent could be selectedsimply by rotating the barrel-type device about its longitudinal axis.

The tube bending machine (described in patent application FR 98/01,315)is secured on the bending arm to the barrel-type device carrying thesets of clamping jaws with different cavities. Each set of clamping jawsconsists of a fixed jaw and a moving jaw making it possible to make anelbow, of a particular bend radius. The barrel-type device can pivot atthe same time as the bending arm about the bending head so as to shapethe tube.

Furthermore, the barrel-type device can move, on the one hand inrotation about its own longitudinal axis and, on the other hand, indirections contained in planes perpendicular and/or parallel to the onecontaining the longitudinal axis of the fixed frame.

SUMMARY OF THE INVENTION

The grasping device according to the present invention is intended tofit around a tube bending machine of standard type without modifying itsstructure and operation.

The grasping device is not secured to the bending head of the bendingmachine but is independent and placed around the latter so that duringthe time of the tube bending cycle it can change the tool or the sets ofclamping jaws.

Grasping device for changing the bending tools on a tube bending machineof standard type, characterized in that it comprises:

a portal frame or the like placed around the bending machine over thebending head and bending arm;

a rotary head which, with respect to the portal frame has independentmovements which consist of two independent or dependent rotations indifferent planes, a vertical movement, and a horizontal movement;

and a tool magazine which can move independently of the movements of therotary head in a horizontal or rotary direction with respect to theportal frame.

Grasping device, characterized in that the rotary head pivots about acentral axle which is inclined by an angle α with respect to ahorizontal plane.

Grasping device, characterized in that the angle α is 45° with respectto a horizontal plane.

Grasping device, characterized in that the portal frame consists of fourvertical legs connected together at the upper part by four horizontalbeams which are arranged in such a way that one of the beams carries therotary head and the tool magazine.

Grasping device, characterized in that the horizontal beam is secured toguide means which collaborate with a crossmember parallel to same beamand able to move in a horizontal direction with respect to the portalframe, said crossmember comprising, on its opposite side to the one thatcollaborates with the guide means, a guide device which allows a supportto move in a vertical direction with respect to the portal frame, saidsupport being secured, at right angles to its vertical axle and in itslower part, to a horizontal beam which, at its free end, carries therotary head constituting the means of grasping the tools or sets ofclamping jaws.

Grasping device, characterized in that the rotary head consists of anarm which can rotate about the central axle which is secured to thehorizontal beam of the support.

Grasping device, characterized in that the arm is secured at each of itsends to a pivot axle each of which collaborates with a fixing devicepivoting about its respective axle to move into a vertical planeparallel to the one containing the support.

Grasping device, characterized in that each fixing device is designed tocarry a set of clamping jaws which consists of a moving jaw and a fixedjaw indexed respectively on the intermediate element of the jaw supportsecured to the bending arm and on the bending roller of the bending headof the bending machine.

Grasping device, characterized in that the arm is secured at each of itsends to a pivot axle which is arranged in a horizontal plane parallel tothe one containing the beam.

Grasping device, characterized in that the horizontal beam is secured,above the guide means, to a horizontal crossmember equipped with guidemeans allowing the tool magazine to slide or rotate.

BRIEF DESCRIPTION OF THE DRAWINGS

The description which will follow with reference to the appendeddrawings given by way of nonlimiting example will allow a betterunderstanding of the invention, of the characteristics it has and of theadvantages it is likely to afford:

FIG. 1 is a perspective view illustrating a tube bending machine ofstandard type around which there is grasping device for changing thebending tools according to the present invention.

FIG. 2 is a detailed depiction of the bending head of the machine abovewhich a set of clamping jaws carried by the grasping device according tothe present invention is mounted.

FIG. 3 is a perspective view showing the grasping device for changingthe bending tools according to the invention.

FIG. 4 is a side view depicting the device for changing tools accordingto the invention.

FIG. 5 is a front view illustrating the grasping device for changing thebending tools according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 and 2 show a bending machine 1 of standard type comprising afixed frame 2 which at one of its ends carries a bending head 3 aboutwhich a bending arm 4 pivots, and a grasping device 5 for changing thebending tools which is arranged above said machine and level with thebending head 3.

The fixed frame 2 comprises, in the known way, and along itslongitudinal axis, a guide rail on which there slides a carriage 6 whichmoves toward and away from the bending head 3.

The carriage 6 carries a mandrel 7 for holding and guiding a tube to bebent, not depicted, which is moved in translation and in rotation aboutits axis.

A device 8 also slides along the longitudinal rail of the fixed frame 2to prevent, using an olive. the tube from being crushed while it isbeing bent.

The bending arm 4 comprises a jaw support 9 which moves horizontally inthe direction of the bending head 3 via hydraulic or pneumatic orelectrical devices known per se.

The jaw support 9 has, on its vertical edge 10 facing the bending head3, a slot 11 in the shape of a T or the like, designed to take anintermediate element 12 intended to collaborate with the moving jaw 13of the set of clamping jaws 14.

The bending head 3 is secured to a bending roller 15, or shaping roller,to which the fixed jaw 16 of the set of clamping jaws 14 is fixed.

The bending roller 15 has a circular profile, part of which is cut outto form a L-shaped cutout allowing the fixed jaw 16 of the set ofclamping jaws 14 to be fitted.

Also, the bending roller 15 comprises, as is known, a peripheral groovewhich communicates with the cavity of the fixed jaw 16, and the bendradius of which can vary according to the shape that the tube is to begiven.

The bending head 3 comprises movement means so that it can movehorizontally and vertically with respect to the fixed frame 2, that isto say in directions in planes perpendicular to the one containing thelongitudinal axis of the machine 1 or of the fixed frame 2.

The grasping device 5 for changing the bending tools or sets of clampingjaws 14 is placed around and over the bending machine 1.

FIGS. 3 to 5 show the grasping device 5 which consists of a portal frame17 or the like with four vertical legs 18 to 21 connected together inthe upper part of the portal frame 17 by horizontal beams 22 to 25. Itis obvious that the portal frame 17 can be replaced by any otherequivalent structure without in any way changing the subject-matter ofthe invention.

The horizontal beam 22 of the portal frame 17 is secured, inside thespace defined by the horizontal beams 22 to 25, to guide means 26 whichcollaborate with a crossmember 27 parallel to said beam 22 and capableof moving in a horizontal direction with respect to said portal frame.

On its opposite face to the face collaborating with the guide means 26,the crossmember 27 has a guide device 28 which is connected to verticaland parallel guides 29 and 30 secured to a support 31 so that the lattercan move in a vertical direction with respect to the portal frame 17.

The support 31 is secured, perpendicular to its vertical axis and in thelower part, to a horizontal beam 32, which, at its free end, carries arotary head 33 constituting the means for grasping the tools or sets ofclamping jaws 14.

The rotary head 33 consists of an arm 34 which can rotate about acentral axle 35 which is secured to the horizontal beam 32 of thesupport 31. The central axle 35 is inclined by an angle α of about 45°with respect to the horizontal plane containing the beam 32.

The inclination of the rotation axle 35 allows the arm 34 of the rotaryhead 33 to be arranged in a plane that is inclined with respect to thehorizontal plane of the beam 32.

This inclination of the rotary head 33 by an angle α frees up asignificant volume around the bending head 3 of the machine 1, making itpossible to create space for handling the already bent tube without thelatter butting against the rotary head.

The arm 34 is secured at each of its ends to a pivot axle 36, 37 whichis arranged in a horizontal plane parallel to the one containing thebeam 32.

Each axle 36, 37 collaborates with a fixing device 38, 39 which canpivot about its respective axle 36, 37 to move into a vertical planeparallel to the one containing the support 31.

Each fixing device 38, 39 carries a set of clamping jaws 14 whichconsists of a moving jaw 13 and a fixed jaw 16 which are designed to beindexed respectively on the intermediate element 12 of the jaw support 9secured to the bending arm 4 and on the bending roller 15 of the bendinghead 3 of the bending machine 1 (FIG. 2).

The horizontal beam 22 of the portal frame 17 is secured, above theguide means 26, to a horizontal crossmember 40 provided with guide means41 allowing a tool magazine 42 to slide or rotate parallel to the beam22.

The tool magazine 42 comprises sets of clamping jaws 14 each setcomprising a moving jaw 13 and a fixed jaw 16. The sets of clamping jaws14 have cavities, the bend radii of which differ so as to allow the samebending machine 1 to perform a number of bending operations on one andthe same tube.

The tool magazine 42 may also carry bending rollers 15 secured to thefixed jaw 16 constituting a monobloc tool and moving jaws 13 formingsets of clamping jaws 14.

The tool magazine 42 is controlled by a central unit, not depicted,which is independent of or identical to the one controlling the bendingmachine 1.

It is noted that the horizontal movements of the tool magazine 42 areindependent of the combined horizontal and vertical movements that allowthe rotary head 33 to move.

The independence of the movements of the tool magazine 42 and of therotary head 33 makes it possible to reduce the cycle time for changingsets of clamping jaws 14 and, more particularly, allows the sets ofclamping jaws 14 to be brought into position which takes place while thetube is being bent on the bending machine 1.

Note that the head 33 has combined movements which consist of twoindependent or dependent rotations in different planes, of a verticalmovement with respect to the portal frame 17 by virtue of the movementof the support 31, and of a horizontal movement with respect to theportal frame 17 via the crossmember 27.

The operation of the grasping device 5 for changing bending tools withrespect to a tube-bending cycle on the machine 1 will have been readilyunderstood from the above description.

For example, it is possible to begin the bending cycle when the bendingarm 4 of the machine 1 is at 0° with respect to the fixed frame 2, thatis to say when it has returned to its origin after the tube has beenbent, as shown in FIG. 1.

Thus, the bending arm 4 and, more particularly, the jaw support 9,carries, via the element 12, a moving jaw 13, whereas the bending roller15 collaborates with a moving jaw 16 forming a first set of clampingjaws 14 which has allowed the tube to be bent.

The grasping device 5 presents the rotary head 33 over the bending head3 and the bending arm 4 by means of a horizontal movement of thecrossmember 27.

With a vertical movement of the support 31, the rotary head 33 isbrought up close to the bending head 3 and bending arm 4.

The rotary head 33 offers up its fixing device 39 which is free andalready positioned in a vertical direction by pivoting about the axle 37over the moving jaws 13 and fixed jaws 16 of the first set of clampingjaws 14.

With a downward vertical movement of the support 31, the rotary head 33collects the moving jaws 13 and fixed jaws 16 of the first set ofclamping jaws 14 on its fixing device 39 by snap-fastening or any othersimilar means of fixing.

By vertical movement of the support 31 with respect to the portal frame17 the rotary head 33 moves back up to extract the moving jaws 13 andfixed jaws 16 from the intermediate element 12 and from the bendingroller 15.

The head 33 pivots about its central axle 35 by half a revolution tooffer up a new set of clamping jaws 14 carried by the fixing device 38over the bending head 3 and bending arm 4. This fixing device is placedin a vertical position by pivoting about its axle 36 so that the movingjaws 13 and fixed jaws 16 of the new set of clamping jaws 14 are in thesame vertical plane as the bending head 3 and the bending arm 4.

The rotary head 33 is lowered via the support 31 to bring the new set ofclamping jaws 14 and, respectively, the moving jaw 13 into theintermediate element 12 of the bending arm 4 and the fixed jaw 16 intothe cutout of the bending roller 15 of the bending head 3.

The moving jaws 13 and fixed jaws 16 of the new set of clamping jaws 14are unlocked from the fixing device 38 by pneumatic means or the like,not depicted, and separated from the fixing device 38 which is then freeand has no sets of clamping jaws as the rotary head 33 is raised again.

At the same time as the new set of clamping jaws 14 is positioned on thebending machine 1, the magazine 42 moves horizontally along the beam 22of the portal frame 17 to present an empty housing for accommodating theset of clamping jaws 14 on the axis of the rotary head 33 and, moreparticularly, facing the fixing device 39.

The rotary head 33 is raised vertically by means of the support 31 withrespect to the portal frame 17, allowing the first set of clamping jaws14 secured to the fixing device 39 to be placed in the selected emptyhousing in the magazine 42.

The rotary head 33 is lowered vertically via the support 31 to leave thesets of clamping jaws 14 in the magazine 42 and free the fixing device39. The magazine 42 moves horizontally along the beam 22 again to offerup another set of clamping jaws 14 to the fixing device 39.

The rotary head 33 is raised up again to fix the other set of clampingjaws 14 on the device 39, while the fixing device 38 is free and has notools.

At the same time as the rotary head 33 and the magazine 42 are moving tounload and load the sets of clamping jaws 14, the bending machine 1proceeds with shaping an elbow in the tube using the set of clampingjaws positioned via the fixing device 38.

As soon as tube bending is complete, the set of steps describedhereinabove are performed again, but this time starting with the fixingdevice 38 which is empty so that it can collect the set of clamping jaws14 loaded onto the machine 1.

What is claimed is:
 1. A grasping device for changing bending tools on atube bending machine, the grasping device comprising: a portal frame(17) adapted to straddle over the bending machine (1) and over a bendinghead (3) and a bending arm (4) of the bending machine; a rotary head(33) which has, with respect to the portal frame (17), independentmovements which consist of two rotational movements in different planes,a vertical movement, and a horizontal movement; and a tool magazine (42)mounted to said portal frame which is movable independently of themovements of the rotary head (33) in a horizontal and/or rotarydirection with respect to the portal frame (17).
 2. A grasping deviceaccording to claim 1, wherein the rotary head (33) pivots about acentral axle (35) which is inclined by an angle (α) with respect to ahorizontal plane.
 3. A grasping device according to claim 2, wherein theangle (α) is approximately 45° with respect to a horizontal plane.
 4. Agrasping device according to claim 1, wherein the portal frame (17)consists of four vertical legs connected together at upper parts thereofby four horizontal beams (22,23,24,25) which are arranged in such a waythat one of the beams (22) carries the rotary head (33) and the toolmagazine (42).
 5. A grasping device according to claim 4, wherein one ofthe horizontal beams is secured to guide means (26) which collaboratewith a crossmember (27) parallel to the one beam (22) and able to movein a horizontal direction with respect to the portal frame (17), saidcrossmember (27) including, on a side opposite to the one side thatcollaborates with the guide means (36), a guide device (28) which allowsa support (31) to move in a vertical direction with respect to theportal frame (17), said support (31) being secured, at right angles toits vertical axis and at a lower part thereof, to a horizontal beam (32)which, at a free end, carries the rotary head (33).
 6. A grasping deviceaccording to claim 5, wherein the rotary head (33) includes an arm (34)which rotates about the central axle (35) which is secured to thehorizontal beam (32).
 7. A grasping device according to claim 6, whereinthe arm (34) is secured at opposite ends thereof to pivot axles (36, 37)each of which support a fixing device (38, 39) such that the fixingdevices are movable in a vertical plane parallel to a vertical planecontaining the support (31).
 8. A grasping device, according to claim 7,wherein each fixing device (38, 39) is adapted to carry a set ofclamping jaws (14) which consists of a moving jaw (13) and a fixed jaw(16) such that the clamping jaws may be indexed respectively on anintermediate element (12) of a jaw support (9) secured to the bendingarm (4) and on a bending roller (15) of the bending head (3) of thebending machine (1).
 9. A grasping device according to claim 7, whereinthe arm (34) is secured at its opposite ends to the pivot axles (36, 37)which are arranged in a horizontal plane parallel to a horizontal planecontaining the beam (32).
 10. A grasping device according to claim 4,wherein the one horizontal beam is secured, above a guide means (26), toa horizontal crossmember (40) equipped with guide means (41) allowingthe tool magazine (42) to slide or rotate.
 11. A grasping deviceaccording to claim 7, wherein each set of the clamping jaws (14)consists of a moving jaw (13) and of a monobloc tool formed of a bendingroller (15) on which a fixed jaw (16) is carried.